The so-called Aroostook War stemmed from a boundary dispute between them:
The so-called Aroostook War stemmed from a boundary dispute that had loomed since 1783 between Maine and New Brunswick and was not settled by the Peace of Ghent. After Maine became a state in 1820, it disregarded British claims in making land grants to settlers along the Aroostook River. The U.S. and Great Britain submitted the dispute to arbitration by the King of the Netherlands in 1827, whose compromise was accepted by the British but rejected by the U.S. Canadian lumberjacks entered the disputed territory n 1838 and began lumbering operations. The arrest by Canadians of a Maine-appointed agent sent into the area to force out the Canadians marked the beginning of the undeclared conflict called the Aroostook War, which saw the Nova Scotia legislature make war appropriations and the U.S. Congress authorize a force of 50,000 men and $10 million. General Winfield Scott brokered a truce between Maine and New Brunswick which averted a real war. The issue was finally settled by a boundary commission and the Webster-Ashburton Treaty of 1842.
